EN ISO 13855:2010

SLOVENSKI STANDARD
01-september-2010
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SIST EN 999:2000+A1:2008
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Safety of machinery - Positioning of safeguards with respect to the approach speeds of
parts of the human body (ISO 13855:2010)
Sicherheit von Maschinen - Anordnung von Schutzeinrichtungen im Hinblick auf
Annäherungsgeschwindigkeiten von Körperteilen (ISO 13855:2010)
Sécurité des machines - Positionnement des moyens de protection par rapport à la
vitesse d'approche des parties du corps (ISO 13855:2010)
Ta slovenski standard je istoveten z: EN ISO 13855:2010
ICS:
13.110 Varnost strojev Safety of machinery
13.180 Ergonomija Ergonomics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 13855
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2010
ICS 13.110 Supersedes EN 999:1998+A1:2008
English Version
Safety of machinery - Positioning of safeguards with respect to
the approach speeds of parts of the human body (ISO
13855:2010)
Sécurité des machines - Positionnement des moyens de Sicherheit von Maschinen - Anordnung von
protection par rapport à la vitesse d'approche des parties Schutzeinrichtungen im Hinblick auf
du corps (ISO 13855:2010) Annäherungsgeschwindigkeiten von Körperteilen (ISO
13855:2010)
This European Standard was approved by CEN on 22 April 2010.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13855:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Annex ZA (informative)  Relationship between this International Standard and the Essential
Requirements of EU Directive 2006/42/EC .4

Foreword
This document (EN ISO 13855:2010) has been prepared by Technical Committee ISO/TC 199 "Safety of
machinery" in collaboration with Technical Committee CEN/TC 114 “Safety of machinery” the secretariat of
which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by November 2010, and conflicting national standards shall be withdrawn
at the latest by November 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 999:1998+A1:2008.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association, and supports essential requirements of EU Directive.
For relationship with EU Directive, see informative Annex ZA, which is an integral part of this document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 13855:2010 has been approved by CEN as a EN ISO 13855:2010 without any modification.
Annex ZA
(informative)
Relationship between this International Standard and the Essential
Requirements of EU Directive 2006/42/EC
This International Standard has been prepared under a mandate given to CEN by the European Commission
the European Free Trade Association to provide one means of conforming to Essential Requirements of the
New Approach Directive 2006/42/EC.
Once this standard is cited in the Official Journal of the European Union under that Directive and has been
implemented as a national standard in at least one Member State, compliance with the normative clauses of
this standard confers, within the limits of the scope of this standard, a presumption of conformity with the
relevant Essential Requirements of that Directive and associated EFTA regulations.
WARNING: Other requirements and other EU Directives may be applicable to the products falling within the
scope of this standard.
INTERNATIONAL ISO
STANDARD 13855
Second edition
2010-05-01
Safety of machinery — Positioning of
safeguards with respect to the approach
speeds of parts of the human body
Sécurité des machines — Positionnement des moyens de protection
par rapport à la vitesse d'approche des parties du corps

Reference number
ISO 13855:2010(E)
©
ISO 2010
ISO 13855:2010(E)
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ii © ISO 2010 – All rights reserved

ISO 13855:2010(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.2
3 Terms, definitions, symbols and abbreviated terms .2
3.1 Terms and definitions .2
3.2 Symbols and abbreviated terms .4
4 Methodology .5
5 General equation for the calculation of the overall system stopping performance and
minimum distances .7
5.1 Overall system stopping performance.7
5.2 Minimum distance .8
6 Calculation of minimum distances for electro-sensitive protective equipment employing
active opto-electronic protective systems.8
6.1 General .8
6.2 Detection zone orthogonal to the direction of approach .9
6.3 Detection zone parallel to the direction of approach .12
6.4 Detection zone angled to the direction of approach .14
6.5 Addressing possible circumventing of electro-sensitive protective equipment by reaching
over the detection zone .16
6.6 Indirect approach — Path from detection zone to hazard zone restricted by obstacles.19
7 Method of calculating the positioning of pressure-sensitive mats or floors .21
7.1 General .21
7.2 Step mounting .22
8 Two-hand control devices .22
9 Interlocking guards without guard locking.22
Annex A (informative) Worked examples .24
Annex B (informative) Termination of hazardous machine functions.33
Annex C (informative) Example for considering indirect approaches .34
Annex D (informative) Measurement and calculation of overall system stopping performance .36
Annex E (informative) Number of beams and their height above the reference plane.38
Bibliography.39

ISO 13855:2010(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 13855 was prepared by Technical Committee ISO/TC 199, Safety of machinery.
This second edition cancels and replaces the first edition (ISO 13855:2002), which has been technically
revised.
iv © ISO 2010 – All rights reserved

ISO 13855:2010(E)
Introduction
The structure of safety standards in the field of machinery is as follows:
a) type-A standards (basic safety standards) giving basic concepts, principles for design, and general
aspects that can be applied to all machinery;
b) type-B standards (generic safety standards) dealing with one safety aspect or one or more type(s) of
safeguard that can be used across a wide range of machinery:
⎯ type-B1 standards on particular safety aspects (e.g. safety distances, surface temperature, noise);
⎯ type-B2 standards on safeguards (e.g. two-hand controls, interlocking devices, pressure-sensitive
devices, guards);
c) type-C standards (machine safety standards) dealing with detailed safety requirements for a particular
machine or group of machines.
This document is a type-B standard as stated in ISO 12100-1.
The requirements of this document can be supplemented or modified by a type-C standard.
For machines which are covered by the scope of a type-C standard and which have been designed and built
according to the requirements of that type-C standard, the following applies: if the requirements of that type-C
standard deviate from the requirements in type-B standards, the requirements of that type-C standard take
precedence over the provisions of other standards.
The effectiveness of certain types of safeguard described in this International Standard to minimize risk relies,
in part, on the relevant parts of that equipment being correctly positioned in relation to the hazard zone. In
deciding on these positions, a number of aspects are taken into account, such as:
⎯ the necessity of a risk assessment according to ISO 14121-1;
⎯ the practical experience in the use of the machine;
⎯ the overall system stopping performance;
⎯ the time taken to ensure the safe condition of the machine following operation of the safeguard, for
example to stop the machine;
⎯ the bio-mechanical and anthropometric data;
⎯ any intrusion by a part of the body towards the hazard zone until the protective device is actuated;
⎯ the path taken by the body part when moving from the detection zone towards the hazard zone;
⎯ the possible presence of a person between the safeguard and the hazard zone;
⎯ the possibility of undetected access to the hazard zone.

INTERNATIONAL STANDARD ISO 13855:2010(E)

Safety of machinery — Positioning of safeguards with respect
to the approach speeds of parts of the human body
1 Scope
This International Standard establishes the positioning of safeguards with respect to the approach speeds of
parts of the human body.
It specifies parameters based on values for approach speeds of parts of the human body and provides a
methodology to determine the minimum distances to a hazard zone from the detection zone or from actuating
devices of safeguards.
The values for approach speeds (walking speed and upper limb movement) in this International Standard are
time tested and proven in practical experience. This International Standard gives guidance for typical
approaches. Other types of approach, for example running, jumping or falling, are not considered in this
International Standard.
NOTE 1 Other types of approach can result in approach speeds that are higher or lower than those defined in this
International Standard.
Safeguards considered in this International Standard include:
a) electro-sensitive protective equipment [see IEC 61496 (all parts)], including:
⎯ light curtains and light grids (AOPDs);
⎯ laser scanners (AOPDDRs) and two-dimensional vision systems;
b) pressure-sensitive protective equipment (see ISO 13856-1, ISO 13856-2 and ISO 13856-3), especially
pressure-sensitive mats;
c) two-hand control devices (see ISO 13851);
d) interlocking guards without guard locking (see ISO 14119).
This International Standard specifies minimum distances from the detection zone, plane, line, point or
interlocking guard access point to the hazard zone for hazards caused by the machine (e.g. crushing,
shearing, drawing-in).
Protection against the risks from hazards arising from the ejection of solid or fluid materials, emissions,
radiation and electricity are not covered by this International Standard.
NOTE 2 Anthropometric data from the 5th to the 95th percentile of persons of 14 years and older were used in the
determination of the intrusion distance value “C” in the equations.
NOTE 3 The data in this International Standard are based on experience of industrial application; it is the responsibility
of the designer to take this into account when using this International Standard for non-industrial applications.
NOTE 4 Data specifically for children have not been used in this International Standard. Until specific data are
available for approach speeds for children, it is the responsibility of the designer to calculate the distances taking into
account that children might be quicker and that a child might be detected later.
ISO 13855:2010(E)
The International Standard is not applicable to safeguards (e.g. pendant two-hand control devices) that can be
moved, without using tools, nearer to the hazard zone than the calculated minimum distance.
The minimum distances derived from this International Standard are not applicable to safeguards used to
detect the presence of persons within an area already protected by a guard or electro-sensitive protective
equipment.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 12100-1, Safety of machinery — Basic concepts, general principles for design — Part 1: Basic
terminology, methodology
ISO 13857:2008, Safety of machinery — Safety distances to prevent hazard zones being reached by the
upper and lower limbs
ISO 14121-1:2007, Safety of machinery — Risk assessment — Part 1: Principles
IEC 61496-1:2004, Safety of machinery — Electro-sensitive protective equipment — Part 1: General
requirements and tests
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12100-1 and the following apply.
3.1.1
actuation
〈safeguards〉 physical initiation of the safeguard when it detects a body or parts of a body
3.1.2
overall system stopping performance
T
time interval between the actuation of the sensing function and the termination of the hazardous machine
function
NOTE Adapted from IEC 61496-1:2004.
3.1.3
detection capability
d
sensing function parameter limit specified by the supplier that will cause actuation of the protective equipment
[IEC/TS 62046:2008, 3.1.4]
3.1.4
electro-sensitive protective equipment
ESPE
assembly of devices and/or components working together for protective tripping or presence-sensing
purposes and comprising at a minimum:
⎯ a sensing device,
2 © ISO 2010 – All rights reserved

ISO 13855:2010(E)
⎯ controlling/monitoring devices,
⎯ output signal switching devices
[IEC 61496-1:2004, definition 3.5]
NOTE ESPEs refer only to non-contact sensing devices.
3.1.5
indirect approach
approach where the shortest path to the hazard zone is obstructed by a mechanical obstacle
NOTE The hazard zone can only be approached by going around the obstacle.
3.1.6
circumventing the detection zone
reaching the hazard zone without actuation of the protective device by passing over, under or to the side of
the detection zone
3.1.7
termination of the hazardous machine function
condition achieved when the hazard parameters are reduced to a level which cannot cause physical injury or
damage to health
NOTE See examples in Annex B.
3.1.8
detection zone
zone within which a specified test piece is detected by the protective equipment
NOTE 1 The detection zone may also be a point, line or plane.
NOTE 2 Adapted from IEC 61496-1:2004, definition 3.4.
3.1.9
minimum distance
S
calculated distance between the safeguard and the hazard zone necessary to prevent a person or part of a
person reaching the hazard zone before the termination of the hazardous machine function
NOTE Different minimum distances may be calculated for different conditions or approaches, but the greatest of
these minimum distances is used for selecting the position of the safeguard.
3.1.10
intrusion distance
C
distance that a part of the body (usually a hand) can move past the safeguard towards the hazard zone prior
to actuation of the safeguard
ISO 13855:2010(E)
3.2 Symbols and abbreviated terms
3.2.1 Symbols
Symbol Term Unit
T overall system stopping performance s
S minimum distance mm
C intrusion distance mm
t reaction time of the protective device s
t stopping time of the machine s
t opening time to open the guard s
K approach speed parameter mm/s
d sensor detection capability mm
H height of detection zone above reference plane mm
h height of the step mm
X distance between the end of the detection zone and the hazard zone mm
S minimum distance when reaching over mm
RO
S minimum distance when reaching through mm
RT
C intrusion distance to the hazard zone when reaching over mm
RO
C intrusion distance to the hazard zone when reaching through mm
RT
a height of the hazard zone mm
b height of the safeguard (e.g. ESPE, protective structure) mm
*
S distance actually covered mm
l ; l ; l shortest distance around obstacles mm
1 2 3
S distance of l , projected on a horizontal plane
1; 1
S distance of l , projected on a horizontal plane mm
;
2 2
S distance of l , projected on a horizontal plane
3 3
e opening size mm
v speed of the opening motion of the power-operated interlocking guard mm/s

3.2.2 Abbreviated terms
AOPD Active opto-electronic protective device
AOPDDR Active opto-electronic protective device responsive to diffuse reflection (e.g. laser scanners)
VBPD Vision-based protective device
ESPE Electro-sensitive protective equipment
4 © ISO 2010 – All rights reserved

ISO 13855:2010(E)
4 Methodology
Figure 1 provides a schematic representation of the methodology for determining the correct positioning of
sensing or actuating devices of safeguards in accordance with this International Standard, which is as follows.
a) Identify the hazards and assess the risks (as specified in ISO 12100-1 and ISO 14121-1);
b) If a type-C standard exists for the machine, select one of the specified types of safeguard from that
machine-specific standard, and then use the distance specified by that standard;
NOTE 1 Type-C standards specify minimum distances directly or by reference to this International Standard.
c) If there is no type-C standard, use the equations in this International Standard to calculate the minimum
distance for the safeguard selected;
NOTE 2 For selection of the appropriate type of safeguard, see ISO 12100-2:2003, Clause 5, and IEC/TS 62046.
d) If it is possible to circumvent (go around) the detection zone, an additional calculation using the equations
in 6.5 shall be made;
e) Where combinations of safeguards are used, a calculation of the minimum distance shall be made, taking
into account each safeguard and possible circumventing;
f) Calculate the minimum distances for each possibility of reaching the hazard zone. Then select the most
protective (greatest) of the minimum distances;
g) If possible, incorporate the distance(s) in the machine design, otherwise see step i);
h) Check that the installation of the safeguard does not allow access without detection. If undetected access
is possible, redesign [step i)], otherwise go to step j);
i) Can parameters be modified or alternative safeguards be used? If neither is possible, additional
safeguards shall be used;
j) Check whether the determined position allows persons to remain between the safeguard and the hazard
zone without being detected. In this case, supplementary measures will be required depending on an
additional risk assessment.
NOTE 3 An example of a supplementary measure is a manual reset switch positioned outside the hazard zone and
the space between the safeguard and the hazard zone. Its position is selected to allow someone operating it to
readily check that no one is within the hazard zone or in the space between the safeguard and the hazard zone. For
the requirements of a manual reset function, see ISO 13849-1:2006, 5.2.2.
ISO 13855:2010(E)
Figure 1 — Methodology
6 © ISO 2010 – All rights reserved

ISO 13855:2010(E)
5 General equation for the calculation of the overall system stopping performance
and minimum distances
5.1 Overall system stopping performance
The overall system stopping performance comprises at least two phases. The two phases are linked by
Equation (1):
Tt=+t (1)
where
T is the overall system stopping performance;
t is the maximum time between the occurrence of the actuation of the safeguard and the output signal

achieving the OFF-state;
t is the stopping time, which is the maximum time required to terminate the hazardous machine
function after the output signal from the safeguard achieves the OFF-state. The response time of the
control system of the machine shall be included in t .
t and t are influenced by various factors, e.g. temperature, switching time of valves, ageing of components.
1 2
t and t are illustrated in Figure 2. t and t are functions of the safeguard and the machine, respectively, and
1 2 1 2
are determined by design and evaluated by measurement. The evaluation of these two values shall include
the uncertainties resulting from the measurements, calculations and/or construction.

a
Actuation of safeguard.
b
Operation of safeguard (OFF signal generated).
c
Termination of hazardous machine function (safe condition).
Figure 2 — Relationship between t and t
1 2
The overall system stopping performance, T, is an essential characteristic for the location of the protective
device. Any deviation of the stopping time of the machine, t , shall be taken into account during the estimation
of T (see Annex D). Where the stopping time can deteriorate during the lifetime of the machine, technical or
organizational measures should be taken to ensure the correct overall system stopping performance. These
measures can be, for example:
⎯ braking performance control devices;
⎯ checks, the nature and the frequency of which should be defined in the user's manual.
NOTE There can be additional aspects to take into account, e.g.:
a) integrity of the protective function (safety in case of faults) (see ISO 13849-1, ISO 13849-2 and IEC 62061);
b) stopping performance monitoring (see, e.g. IEC/TS 62046);
ISO 13855:2010(E)
c) cases where inadequate stopping performance prevents the application of this International Standard, e.g.
1) it is not possible to stop the machine during a cycle, or
2) the stopping performance cannot be predicted.
Measurements of stopping performance of a system require careful consideration in order to obtain accurate
and relevant values. Annex D gives guidance on the steps to take to ensure appropriate results.
5.2 Minimum distance
The minimum distance to the hazard zone shall be calculated by using the general Equation (2).
SK=×()T+C (2)
where
S is the minimum distance, in millimetres (mm);
K is a parameter, in millimetres per second (mm/s), derived from data on approach speeds of the body
or parts of the body;
T is the overall system stopping performance, in seconds (s), (see 3.1.2 and 5.1);
C is the intrusion distance, in millimetres (mm).
Clauses 6 to 9 show how this equation is used with particular types and arrangements of protective devices.
For worked examples, see Annex A.
6 Calculation of minimum distances for electro-sensitive protective equipment
employing active opto-electronic protective systems
6.1 General
6.1.1 This clause specifies requirements for two main situations based on the direction of approach of the
person or part of the person's body being:
a) orthogonal (at right angles or normal) to the detection zone (see 6.2), or
b) parallel to the detection zone (see 6.3).
Requirements are also provided for arrangements where:
⎯ an angled approach (between orthogonal and parallel) needs to be considered (see 6.4);
⎯ it is necessary to address possible circumventing of the electro-sensitive protective equipment (see 6.5);
⎯ the path from the detection zone to the hazard zone is restricted by obstacles (indirect approach)
(see 6.6).
NOTE 1 These situations also appear in combination.
Where the minimum distance is such that it would allow a person to remain undetected between the detection
zone and the hazard zone, additional presence-sensing equipment or other solutions should be provided to
prevent this.
NOTE 2 This International Standard is not intended to provide measures against reaching a hazard zone by climbing
over.
8 © ISO 2010 – All rights reserved

ISO 13855:2010(E)
6.1.2 Safeguards shall be configured and positioned such that undetected access to the hazard zone is not
possible.
6.1.3 Where necessary, additional safeguards shall be provided to prevent circumventing the detection
zone of the safeguard (see Figure 9).
6.1.4 For the use of laser scanners (AOPDDR) or vision-based protective devices (VBPD) with a two-
dimensional protection zone, the calculation of the minimum distance shall be in line with 6.2, 6.3 or 6.4,
depending on the approach direction.
6.2 Detection zone orthogonal to the direction of approach
6.2.1 General
Figure 3 gives three examples where the detection zone is orthogonal to the direction of approach.

a) b)
c)
Key
1 hazard zone S minimum distance
a
2 detection zone Direction of approach.
3 fixed guard
Figure 3 — Three examples where the detection zone is orthogonal to the direction of approach
ISO 13855:2010(E)
6.2.2 Vertical detection zones detecting whole body access
When the safeguard is used only for the detection of whole body access:
a) the height of the lowest beam shall be u 300 mm to prevent access under the detection zone. Where it is
foreseeable that electro-sensitive protective equipment will be used in non-industrial applications, for
example in the presence of children, the height of the lowest beam shall be < 200 mm;
b) the height of the uppermost beam shall be W 900 mm to prevent stepping over the detection zone. This is
not applicable for single beams or for detection zones parallel to the direction of approach (see 6.3).
6.2.3 Electro-sensitive protective equipment employing active opto-electronic protective devices
with a sensor detection capability of u 40 mm in diameter
6.2.3.1 Calculation
The minimum distance, S, in millimetres, from the detection zone to the hazard zone shall not be less than that
calculated using Equation (2):
SK=×()T+C (2)
where
K = 2 000 mm/s;
C = 8 (d − 14), but not less than 0;
d is the sensor detection capability of the device, in millimetres (mm).
Then
ST=×(2 000 )+ 8(d−14) (3)
Equation (3) applies to all minimum distances of S up to and including 500 mm. The minimum value of S shall
be 100 mm.
Where the values for S, calculated using Equation (3), exceed 500 mm, Equation (4) can be used. In this case,
the minimum value of S shall be 500 mm.
SK=×()T+C (2)
where
K = 1 600 mm/s;
C = 8 (d − 14), but not less than 0;
d is the sensor detection capability of the device, in millimetres (mm).
Then
ST=×(1600 )+ 8(d−14) (4)
Where it is foreseeable that electro-sensitive protective equipment employing active opto-electronic protective
devices will be used in non-industrial applications, for example in the presence of children, the minimum
distance, S, shall be calculated with Equation (3) and be increased by at least 75 mm. In such cases,
Equation (4) is not applicable.
10 © ISO 2010 – All rights reserved

ISO 13855:2010(E)
6.2.3.2 Cycle re-initiation of machine operation employing active opto-electronic protective devices
with control function
Where active opto-electronic protective devices are used for cycle re-initiation of a machine
⎯ their sensor detection capability shall be u 30 mm,
⎯ Equation (3) (see 6.2.3.1) shall apply, and
⎯ the minimum distance, S, shall be > 150 mm.
If the sensor detection capability is u 14 mm,
⎯ Equation (3) shall apply, and
⎯ the minimum distance, S, shall be > 100 mm.
NOTE 1 Conditions for using electro-sensitive protective equipment in cycle initiation of machine operation are given in
ISO 12100-2:2003, 5.2.5.3, and IEC/TS 62046:2008, 5.6.
NOTE 2 Additional requirements for electro-sensitive protective equipment are given in IEC 61496-1.
NOTE 3 It is possible for electro-sensitive protective equipment with a sensor detection capability > 30 mm diameter to
not detect the wrist or the lower arm after the hand has been detected. An unexpected cycle re-initiation can occur.
6.2.4 Electro-sensitive protective equipment with a sensor detection capability of > 40 mm and
u 70 mm diameter
Electro-sensitive protective equipment with a sensor detection capability of > 40 mm and u 70 mm diameter
do not detect intrusion of the hands and, therefore, shall only be used where the risk assessment indicates
that detection of intrusion of the hands is not necessary.
This equipment shall be installed in accordance with the following parameters.
The minimum distance from the detection zone to the hazard zone shall be calculated using Equation (5).
SK=×()T+C (2)
where
K = 1 600 mm/s;
C = 850 mm.
Then
ST=×(1600 )+ 850 (5)
NOTE 850 mm is considered to be the standard arm reach.
6.2.5 Multiple separate beams
Arrangements of 2, 3 or 4 separate beams can be used to detect intrusion of the whole body into the hazard
zone but are not suitable for detecting parts of the body (e.g. hand or fingers).
If the risk assessment indicates that multiple separate beams are appropriate, they shall be positioned at a
minimum distance from the hazard zone in accordance with Equation (5) (see 6.2.3).
ISO 13855:2010(E)
During risk assessment, methods which can possibly be used to bypass such equipment shall be taken into
account. The risk assessment shall consider methods by which beam arrangements can be circumvented. For
example:
⎯ crawling below the lowest beam;
⎯ reaching over the top beam;
⎯ reaching through between two of the beams;
⎯ bodily access by passing between two beams.
For additional information, see Annex E.
6.2.6 Single beams
These beams have only been considered when they are used parallel to the ground and the beam is broken
by a person's body in the upright position. A single beam as the only means of protection is not suitable for
preventing whole body access.
NOTE A single beam device is normally used in combination with other safeguards or other structures, which restrict
the opening(s) such that it is not possible to pass the protective device without being detected.
The minimum distance, S, shall be calculated according to Equation (6)
ST=×1600 +1200 (6)
()
A height of 750 mm from the ground or reference plane (see ISO 13857) has been found in industry to be a
practical solution to the problems of inadvertent access from stepping over or bending under the beam.
6.3 Detection zone parallel to the direction of approach
See Figure 4.
12 © ISO 2010 – All rights reserved

ISO 13855:2010(E)
Key
1 hazard zone H height of detection zone above reference plane
2 detection zone S minimum distance
3 edge of the detection zone X distance between the end of the detection zone and the hazard zone
a
4 fixed guard Direction of approach.
Figure 4 — Detection zone parallel to direction of approach
When the direction of approach is parallel to the detection zone, the minimum distance, S, shall be calculated
using Equation (7).
SK=×()T+C (2)
where
K = 1 600 mm/s;
C = 1 200 mm − 0,4 H, but not less than 850 mm, where H is the height of the detection zone above
the reference plane, for example the floor, in millimetres (mm).
Then
ST=×(1600 )+ (1200− 0,4H ) (7)
For a safeguard where the direction of approach is parallel to the detection zone, the height, H, of the
detection zone shall not be greater than 1 000 mm. However, if H is greater than 300 mm (200 mm for non-
industrial applications, for example in the presence of children) there is a risk of inadvertent undetected
access beneath the detection zone. This shall be taken into account in the risk assessment and additional
protective measures applied, if necessary.
The lowest allowable height of the detection zone shall be calculated using Equation (8).
Hd=−15( 50) (8)
If d is less than 50 mm, H shall never be less than 0.
ISO 13855:2010(E)
Thus, for a given height of the detection zone, the corresponding sensor detection capability, d, shall be
calculated using Equation (9).
⎛⎞H
d=+ 50 (9)
⎜⎟
⎝⎠
That means, where the height of the detection zone is known or fixed, a maximum sensor detection capability
can be calculated.
For example, when calculating the horizontal section of L-shaped electro-sensitive protective equipment or if a
sensor detection capability is known or fixed, a minimum height can be calculated, up to the allowable
maximum of 1 000 mm.
When using the device as both a trip and presence-sensing device, the distance X (see Figure 4) shall not be
less than the detection capability, d.
Measures shall be applied so that the protective devices cannot be used to gain access to the hazard zone
(e.g. by stepping or climbing on the housing).
6.4 Detection zone angled to the direction of approach
If the detection zone has been installed such that it is angled greater than ± 30° of the direction of approach, it
shall be treated as an orthogonal approach [see 6.2 and Figures 5 a) and 6].
If the detection zone has been installed such that it is angled less than ± 30° of the direction of approach, it
shall be treated as a parallel approach [see 6.3 and Figures 5 b) and 6].
A tolerance of ± 5° should be used for these angles.

a)  Orthogonal approach b)  Parallel approach
Key
1 hazard zone S minimum distance
a
2 detection zone Direction of approach.
3 fixed guard
4 edge of detection zone
Figure 5 — Detection zone angled to the direction of approach
14 © ISO 2010 – All rights reserved

ISO 13855:2010(E)
Key
1 locations of ESPE at different angles to the direction of approach
a
Direction of approach.
b
Angles of parallel approach; less than ± 30°.
c
Angles of orthogonal approach.
Figure 6 — Different angles to the direction of approach
When an angled approach is considered as parallel approach (see Figure 6), then Equation (8) linking H and d
(see 6.3) shall apply to the edge of the detection zone furthest from the hazard zone (see Figure 7).
NOTE In some applications the detection zone could extend more than 1 000 mm above the reference plane. For
calculations using Equation (7), parts of the detection zone greater than 1 000 mm above the reference plane are not
considered.
Key
1 hazard zone H height of the detection zone (lowest beam)
2 detection zone S minimum distance
a
3 edge of detection zone Direction of approach.
4 fixed guard
Figure 7 — Height of the detection zone (lowest beam)
ISO 13855:2010(E)
6.5 Addressing possible circumventing of electro-sensitive protective equipment by
reaching over the detection zone
6.5.1 General
Access to the hazard zone by circumventing of the electro-sensitive protective equipment shall be avoided.
NOTE This can be achieved by the provision of guards or other protective measures.
If access to the hazard zone by reaching over the detection zone of vertically mounted electro-sensitive
protective equipment cannot be excluded, the height and the minimum distance, S, of the safeguard shall be
determined. S shall be determined by comparison of the calculated values in 6.2 and 6.3 based on the
approach of limbs or parts of the body and the values for reaching over determined in 6.5.2, 6.5.3 and 6.5.4.
The greater value resulting from this comparison shall be applied.
6.5.2 Prevention of reaching over a vertical detection zone of electro-sensitive protective equipment
without an additional protective structure
The minimum distance, S, in millimetres from the detection zone to the hazard zone for prevention of
circumventing by reaching over the ESPE shall not be less than that calculated using Equation (10).
For C , the values in Table 1 shall apply. C is given in this table as the additional dis
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